Host Protocols Smart Reader Protocols $SCRDR Messages
March 13, 2024 at 8:13 AMSpringCore $SCRDR Messages
SpringCore devices configured for Smart Reader operation support using $SCRDR Messages to communicate over different channels. $SCRDR Messages use a simple ASCII formatting.
Channels supporting $SCRDR Messages
$SCRDR messaging has to be enabled by setting appropriate value to 03 in register 02A0
Message Structure
- All transmitted data are printable ASCII characters between
20(space) to7E(~). - Data characters are all the above characters, expect the reserved characters listed below.
- Reserved characters are:
| ASCII | Hex | Dec | Meaning |
|---|---|---|---|
<CR> |
0D |
13 | Carriage return |
<LF> |
0A |
10 | Line feed, end delimiter |
$ |
24 |
36 | Start delimiter |
* |
2A |
42 | Checksum delimiter |
; |
3B |
59 | Field delimiter |
- The start character for each message is a
$; the next two characters identify the SpringCard/SpringCore family (SC) and then the next three characters identify the type of message. - All data fields that follow are delimited by a semi-colon
;. - Fields having no data, or where data is not significant, are left empty (no character before the next delimiter).
- The checksum is the bitwise XOR of ASCII codes of all characters between the
$and*(both delimiters are not included in the checksum). The checksum is expressed as a two-digit hexadecimal number.